Rates of women who are opting for preventive mastectomies, such as Angeline Jolie, have increased by an estimated 50 percent in recent years, experts say. But many doctors are puzzled because the operation doesn't carry a 100 percent guarantee, it's major surgery -- and women have other options, from a once-a-day pill to careful monitoring.

And when nonsmokers move in, they may absorb these toxic chemicals even if the home has been cleaned and vacant for months, researchers found.

The pollutants, which have been labeled “thirdhand smoke,” can coat all the surfaces of a dwelling and seep into every crevice, said the study’s lead author, Georg E. Matt, a professor of psychology at San Diego State University.

“These oily, sticky droplets hang around for months after a smoker has left,” Matt said. “While there was considerably less in homes once an active smoker moved out, there was still 10 to 20 percent of what was found while the smoker still lived there.”

Rates of women who are opting for preventive mastectomies, such as Angeline Jolie, have increased by an estimated 50 percent in recent years, experts say. But many doctors are puzzled because the operation doesn't carry a 100 percent guarantee, it's major surgery -- and women have other options, from a once-a-day pill to careful monitoring.

Matt and his colleagues studied nicotine levels as a marker for other chemical residues from tobacco smoke in the dwellings of 100 smokers and 50 nonsmokers who were planning to move out of their homes. The researchers measured the chemical in the air and on surfaces, such as walls, ceilings and floors. At the same time, they checked for nicotine on the fingertips of the residents of the 150 homes and a nicotine breakdown product called cotinine in urine samples from children.

Next, the researchers looked at nonsmokers who moved into 25 of the homes that had formerly been occupied by smokers. Once again, Matt and his colleagues measured nicotine on the adults’ finger tips and cotinine in the children’s urine.

The results were striking. Even after the smoker homes had been vacant for two months, nicotine levels in the air were 35 to 98 times as high as they were in nonsmoker homes. Nicotine measured on surfaces was 30 to 150 times as high in the former homes of smokers compared to what was found in dwellings of nonsmokers.

More troubling were the findings of nicotine on or in the bodies of nonsmokers who had moved into dwellings formerly occupied by smokers. Nicotine levels were seven to eight times higher on the fingertips of nonsmokers who’d moved into a smoker’s home compared to nonsmokers who had always lived in a nonsmoking home. Children who’d moved into a home formerly occupied by a smoker had three to five times as much cotinine as those who lived in a nonsmoking home.

Tips: What you can do

If you’ve moved into a home that was previously occupied by a smoker, what can you do to minimize the risk that you and your children will be exposed smoke residues?

Experts recommend first that you get rid of carpeting and clean fabrics, such as curtains. Next, you might want to wash down the walls and ceilings and then clean floors with household vinegar, said Georg Matt, professor of psychology at San Diego State University.

Another strategy if you’re not sure about the smoking history of a home is to take samples on your own and send them out to a lab for testing, said Stephanie Land, an associate professor in the department of biostatics at the University of Pittsburgh Cancer Institute.

Further, Land said, there are also companies that clean up homes that have been exposed to tobacco smoke. “I don’t know if there’s any evidence out there to show how effective those companies are, but it might be worth a try.”

In a home were heavy smoking has been going on for years, you might need more drastic measures, such as replacing the dry wall and tiles to get rid of chemical residue, Matt said.

“This is a cool study,” said Dr. Reynold Panettieri, Jr., an expert on the impact of pollutants on lung health and director of the Airways Biology Initiative at the University of Pennsylvania School of Medicine. “It was meticulously done. And while we don’t yet know the health consequences of thirdhand smoke, you have to remember that it took 20 years before we realized that smoking could lead to cancer and another 20 before we realized secondhand smoke could lead to cardiovascular disease.”

Until we learn more about the impact of thirdhand smoke, it might make sense to err on the side of caution, especially when it comes to small children, said Stephanie Land, an associate professor in the department of biostatics at the University of Pittsburgh Cancer Institute.

Land recommended washing down any surface a young child might touch, such as doors, floors and walls. “Anywhere a child might touch and then put his fingers in his mouth,” Land said.

Ultimately, you’re in better shape if you can’t smell smoke residue in the home since it means that pollutant levels are probably lower.

“Above a certain threshold level, you can smell it,” Matt said. “And if you can smell it, that means you’re inhaling these compounds and they’re going into your lungs. So smelling is a good indicator though it’s not a super sensitive one.”